Rename master branch to main

I suggest renaming the default branch for the AWS provider to main and retire master.

See:

Hi @YakDriver! Thanks for bringing this up.

I’m on the Terraform Core team rather than the AWS provider team so I can’t speak to the provider codebase plans specifically, but I just wanted to let you know that all of HashiCorp’s projects will be gradually transitioning to using main as the primary branch, and there is work underway to be able to make that change.

Many of the HashiCorp projects have large repositories with lots of open pull requests, ongoing development, CI integration configurations which have branch names encoded in them, etc. Therefore a team at HashiCorp is developing some tools to help make these changes safely and with minimal disruption across each project.

I can’t say when each individual repository will change because that’ll be driven by each of the teams’ local constraints, but hopefully the above is helpful context for what is going on. Thanks again!